Nearly 2,000 gallons of mostly methanol, mixed with some crude oil and water, spilled onto a frozen tundra pond and a gravel pad from a pipeline, the Department of Environmental Conservation said. The spill occurred on Monday.

Methanol, which is poisonous to plants and animals, is used to clear ice from the insides of the Arctic-based pipelines, said Ed Meggert an agency official in Fairbanks.

Two officials from the department are investigating the cause of the spill and will make recommendations for clean-up, Meggert said.

Methanol is soluble in water, so a clean-up company is flooding the pond with warm water and will vacuum up the fluids, Meggert said.

The spill came from a five-mile pipeline that carries oil along with the water and gas that wells up with it from underground reservoirs at the nation's largest oil field.

The pipe had been emptied and cleaned for inspection and repairs several weeks ago, said BP spokesman Steve Rinehart.

"We were bringing it back online and discovered an ice blockage, so in the course of trying to clear the blockage, we ran a solution of methanol and water into the pipe," he said. "Through some mechanism that we'll discover through an investigation, something occurred that caused the spill."

No one was hurt, Rinehart said, and the London-based company has notified the requisite state and federal agencies.

BP is undergoing a massive restructuring following several high-profile setbacks. In the past few years, the company has been hit by a deadly Texas refinery accident, oil spills at Prudhoe Bay and delays at its Gulf of Mexico oil and gas projects.